Coronavirus means you’re travelling between particular countries, you may have to observe a 14 day quarantine when you arrive.
One in five eligible passengers will be called or texted to check they are following the rules.
People who do not self-isolate can be fined up to £1,000 in England, Wales and Northern Ireland and £480 in Scotland.
There are fines up to £5,000 for persistent offenders.
But what do you have to do if you’re asked to quarantine?
BBC Health Correspondent Laura Foster explains what you need to do.